Railway interlocking control system



June 16, 1959 c. D. lHRlG 2,891,142

RAILWAY INTERLOCKING CONTROL SYSTEM Filed Sept. 28, 1954 9 Sheets-Sheet 1 Track Model Diqqmm O 2L0- 2124K 21250 1 Z 0- g V fi E240 WN V v 2m am? 41.60 I 15W 290 55W 450 June 16, 1959 c. D. IHRIG 2,891,142

RAILWAY INTERLOCKING CONTROL SYSTEM Filed Sept. 28, 1954 9 Sheets-Sheet 2 I I r 41m? 4102 g INVENTOR.

CliFFord D. llmig [291a BY MAW- HIS ATTORNEY June 16, 1959 c. D. IHRIG 2,891,142

RAILWAY INTERLOCKING CONTROL SYSTEM Filed Sept. 28. 1954 9 Sheets-Sheet a June 16, 1959 c. D. lHRlG RAILWAY INTERLOCKING CONTROL SYSTEM Filed Sept. 28. 1954 9 Sheets-Sheet 4 Clifford D. llzry BY HIS ATTORNEY June 16, 1959 c. D. lHRlG I 2,891,142

RAILWAY INTBRLOCKING CONTROL SYSTEM Filed Sept. 28, 1954 9 sheets sheet 5 June 16, 1959 C. D. IHRIG RAILWAY INTERLOCKING CONTROL SYSTEM F illd Sept 28, 1954 9 Sheets-Sheet 6 INVEN TOR. ULIJfFord D. 112119 HIS ATTORN Y June 16, 1959 c. D. lHRlG RAILWAY INTERLOCKING CONTROL SYSTEM Filed Sept. 28. 1954 9 Sheets-Sheet '7 June 16, 1959 c. D. IHRI G RAILWAY INTERLOCKING CONTROL SYSTEM Filed Sept. 28, 1954 9 Sheets-Sheet 8 v INVENTOR. C'Liiford D Ibriy ulL HIS ATTORNEY "June 16, 1959 c. D. 4R1; 2,891,142

RAILWAY INTERLOCKING CONTROL SYSTEM Filed Sept. 28, 1954 9 Sheets-Sheet 9 016 286. flatz'on.

my 1a. my 10. Fig: 10. my 1g my. 16. my id. FL'gZE F 1h INVENTOR. C'lififiord 0 1121119 BY MAW- HIS ATTORNEY States Patent 2,891,142 Patented June 16, 1959 2,891,142 RAILWAY INTERLOQKHN'G CONTROL SYSTEM Clitlord D. Ihrig, Penn Township, Allegheny County, Pa.,

assignor to Westinghouse Air Brake Company, Wilmerding, Pin, a corporation of Pennsylvania Application September 28, 1954, Serial No. 458,726

4 Claims. (Cl. 246--3) My invention relates to railway interlocking control systems, and more particularly to railway interlocking control systems of the type which employ relay networks only, without mechanical locking, for providing the necessary interlocking between the various switches and signals of the interlocking, and also to provide additional locking protection to prevent improper operation of the apparatus.

It has previously been proposed to provide in systerns of this character, indication lamps mounted on a control board or on another suitable surface, indicating the established exit ends of routes which-are set up for trains to move through the interlocking. These exit lamps are controlled by the circuits which govern the selection of routes through the interlocking plant, and provide the operator of the interlocking control machine with a knowledge that the route which he has selected has been established, so that a signal may thereafter be cleared to permit a train movement over the established route.

One such arrangement of exit lamps in connection with an interlocking system is shown in Letters Patent of theUnited States No. 2,567,834, issued on September 11, 1951, to Earl M. Allen for Centralized Traffic Control Systems for Railways, for the code control of interlocked track switches and signals.

My invention constitutes an improvement over the arrangement shown in the Allen patent referred to above, in that a plurality of exit relays connected in a suitable network is provided for checking the agreement between the switch levers and the switch machines which operate the track switches, the exit relays when energized lighting the exit lamps on the track model diagram and providing suitable control circuits for enabling the wayside signals to be cleared.

Another feature of my invention is the provision of a control circuit in which, after a route has been established as indicated by the lighting of a suitable exit lamp, the signal control lever may be pushed or a separate push button associated with the lever maybe pushed to thereby finally clear the wayside signal after the operator of the control machine has been assured that the route which has been established is the one which he desires the train to follow.

One object of my invention is to provide an improved circuit arrangement for governing the operation of a railway interlocking control system, in which exit lights are provided on a track model diagram for indicating to the operator of the interlocking machine whether or not a route has been set up for a train to move through the interlocking, the circuits being arranged to use a minimum number of relays and contacts.

A further object of my invention is to provide an improved arrangement of the type described, in which exit relays are governed by a network including contacts of the switch control levers and the switch indication relays, so that the exit relays are energized when a route has been set up through the interlocking plant,

and by providing an exit relay repeater relay which is energized when a push button associated with the signal lever is operated, to thereby maintain the exit relays energized even though the push button is thereafter released. The exit relays and the exit. relay repeater relays govern a route agreement network including contacts governed by the position of the track switches, so that, when a check is obtained that a complete route has been set up, the route agreement relays will be energized and cause the appropriate signal to be cleared.

Other features of my invention and points of novelty thereof will become apparent from the following de scription taken in connection with the accompanying drawings.

In practicing my invention, I provide associated with the control machine, a lever agreement network which includes contacts of the switch control and signal control levers, and contacts of the switch indication relays, which network is arranged so that, when a route has been set up by operation of the switch control levers and the associated track switches have operated in accordance therewith, an exit relay is energized to indicate the point of exit of the train from the interlocking. The exit relays govern a suitable circuit network for supplying energy to exit lamps on the track model diagram, so that the selected point of exit for the route is indicated to the control operator. If the route indicated by the exit lamp corresponds with that desired by the operator, he then depresses a push button associated with the signal lever, or which may form a part of the signal lever itself, to thereby energize an exit relay repeater relay over another network including contacts of the switch indication relays and signal lever contacts. The exit relay repeater relays close suitable stick circuits for maintaining the exit relays energized independently of the switch position checking network. The energization of the exit relay repeater relays supplies energy to a route agreement relay network, including contacts of the switch correspondence relays which guarantee that the track switches are in their proper position, whereupon the route agreement relays will pick up their contacts, to form stick circuits for maintaining the exit relay repeater relays and the exit relays energized and also to energize a suitable signal control network for clearing the associated wayside signals. Thus, after a route has been established and the appropriate wayside signal has been cleared, the inadvertent operation of any lever other than the signal control lever for the particular signal which has been cleared will not result in placing the signal at stop.

I shall describe one form of railway interlocking control system embodying my invention, and shall then point out the novel features thereof in claims.

Referring to the accompanying drawings, Figs. 1a to 1h, inclusive, arranged in the manner shown in Fig. 2, show the circuits and apparatus involved for the control of a typical railway interlocking layout.

In the interests of clarity, a track layout of minimum size has been chosen to illustrate the embodiment of the invention, and as shown by the track plan in Fig. 1g, this layout comprises a track section 1T containing a single track switch designated by the reference character 1W, the track section lT extending between the signals ZRA and ZRB at the left-hand end of the interlocking and signal 2L at the right-hand end of the interlocking. A crossover including the track switches SW and 3AW con nects track section 1T with a corresponding section ST in a parallel stretch of track, section 3T extending between the home signals iR at the left-hand end of the stretch and 4L at the right-hand end of the stretch.

The switches and signals for this interlocking are governed by a suitable control machine, shown diagrammatically in Figs. la and lb, and comprising a track model diagram as shown at the top of Fig. 1a, and including control levers such as levers 15W and 35W for governing the operation of the switch 1 and the crossover 3, signal levers such as levers 286 and 48G which govern the operation of the signals for permitting train movements over the interlocking plant, and suitable indication lamps for indicating to the operator of the control machine the tratfic conditions existing in the interlocking plant. Although not shown herein, indication lamps may be provided for each of the control levers to indicate the condition of the functions governed by these levers, but since these indication circuits form no part of my invention and may be arranged in any one of a number of manners well known in the art, they are not shown.

The track model diagram includes a plurality of exit lights such as exit lamps ZRBX, ZRAX, l-RX, 2LX, and 4LX, the position of these lamps being shown in the drawings as being located at the various exit points for train movements through the interlocking plant. The manner in which these lamps are controlled will be explained in detail subsequently.

Each of the control levers for the interlocking machine governs the operation of a plurality of contacts, shown as a plurality of circles associated with each of the levers, the letter designation within the circle indicating the position of the lever in which the contact is closed, for example, the letter L indicating that the contact is closed when the associated lever is operated to its lefthand position from its center or normal position, in the ease of a signal lever, which has a normal position with the lever in the center, and which may be operated either to the left or to the right to govern a signal in the corresponding direction, while the switch levers each have a normal position to the left and a reverse position to the right for governing the corresponding switches to their normal or reverse positions.

The apparatus further includes a plurality of relays for carrying out the various control and indication functions as well as providing the necessary interlocking between the switches and signals. These relays include exit relays such as relays ZRXR, ZLXR, 4RXR, and eLXR; exit relay repeater relays such as relays ZXPR and 4XPR; switch indication relays such as relays lNWK, IRWK, SNWK, and SRWK, all of the foregoing relays usually being provided in the control machine; route agreement relays such as relays ZRHSR, ZLHSR, 4RHSR, and 4LH S R; switch correspondence relays such as relays INWCR, IRWCR, 3NWCR, and 3RWCR; signal looking relays such as relays ZRASR, ZLASR, 4RASR, and 4LASR; time element relays such as relays ZTER and ATER for providing a time release of the signal locking relays; a route locking relay EWSR; switch locking-relays 1LR and SLR; switch control relays such as relays lWR and 3WR; signal control relays such as relays ZRAHR, ZRBHR, 4RHR, ZLHR, and 4LHR; track repeating stick relays such as relays llTPSR and 3TPSR, and track relays such as relays 1T R and 3TR.

The track sections IT and 3T are each equipped with a conventional direct current track circuit of the type having a battery connected across the rails at one end of the section and having the associated track relays l TR and 3TR connected across the rails of their respectivesections at the end opposite the end to which the battery is connected. Energy for the operation of the apparatus other than the track circuits is furnished by a suitable source of low voltage direct current, not shown, the positive and negative terminals of which are I designated by the reference characters B and N, respectively. The wayside signals may be any one of the vari ous types well known in the art, and are here shown as being of the color light type having a yellow lamp Y and a red lamp R which, when lighted indicate proceed with caution and stop, respectively.

Similar reference characters refer to similar parts in each of the several views.

The operation of the system of my invention will now be described under different assumed conditions, starting with the apparatus in its normal condition as shown in the drawings, with the switch 1 and the cross-over 3 in their normal position, and each of the wayside signals displaying a stop aspect.

At this time, the track relays ITR and 3TR will each be picked up since no train is occupying either of the associated track sections IT and 3T, and the track repeater stick relays ITPSR and 3TPSR are each supplied with energy by a circuit including the front con tact a of the associated track relay and a front contact a of the associated track repeating stick relay. Each of the signal control relays is released, the back contact a of each of these relays establishing a circuit for supplying energy to the red lamp R of the associated signal, so that each of the wayside signals displays a red aspect. With all the signals at stop, the back contacts b of the signal control relays are closed in circuits for energizing the four approach locking relays ZLASR, 4LASR, ZRASR and 4RASR, so that these relays have their contacts picked up at this time. The route locking relay lWSR is picked up, and the switch locking relays lLR and 3LR are each picked up, the front contacts b and c of the switch locking relays being closed in the circuits for energizing the switch control relays iWR and SWR, and since the switch levers 118W and 38W are in their normal position, energy is supplied over the contacts of these levers to energize the switch control relays with energy of normal polarity so that the contacts of the switch control relays are picked up and the polar contacts of the relays occupy their normal position, in which energy is supplied to the switch movements ISM, 38M, and '3ASM to maintain the switch l and crossover 3 in their normal position. With the polar contacts 0 of the switch control relays in their normal position, obvious circuits are established for energizing the windings of the switch correspondence relays INWCR and 3NWCR over circuits including contacts in the switch circuit controllers associated with the switch movements, these contacts being closed with the switches in their normal position. Relays INWK and SNWK are energized by energy supplied over obvious circuits including the front contacts a of relays INWCR and SNWCR so that relays INWK and 3NWK are picked up at this time.

With the signal levers 286 and 45G standing in their normal or .center position, the various exit relays, exit relay repeater relays, and route checking relays are all released.

It will now be assumed that the operator desires to set up a route for a train to move past signal ZRB, over switch .1 .and crossover 3 reverse, and depart from the interlocking past signal 4L. Accordingly, the operator will position the switch levers 18W and SSW to their right-hand or reverse position, and will operate the signal lever 28G .to its right-hand position. The contacts r: and d of lever 15W are opened at this time and contacts e and f of this lever are now closed, so that the polarity of the energy supplied over front contacts b and c of relay lLR to the winding of switch control relay lWR is reversed. Similarly, contacts d and e of switch lever 38W are now opened and contacts 1 and g are closed, thereby reversing the polarity of the energy supplied over front contacts b and c of the locking relay 3LR tov the winding of the switch control relay 3WR. As a result the contacts of the switch control relays 1WR and 3WR are operated to their reverse position, thereby closing circuits for supplying energy to the switch movements ISM, 35M, and 3ASM, so that these switch movements operate to reverse their respective track switches. With the polar contacts c of relays IWR and 3WR operated to their right-hand or reverse position. circuits are established over the switch circuitcontrollers of the associated switch movements when the switch is closed and locked in its reverse position, to result in the energization of the switch correspondence relays IRWCR and SRWCR, and the release of the normal switch correspondence relays INWCR and SNWCR.

The switch indication relays lNWK and 3NWK are deenergized and their contacts are released, and at the same time the closing of front contacts a of relays lRWCR and 3RWCR establishes circuits for energizing the switch indication relays IRWK and 3RWK so that the contacts of these relays are picked up.

A circuit is now established for energizing the exit relay 4LXR, designating the right-hand end of section 3T as the exit end of the route, which circuit may be traced from terminal B at back contact a of relay ZRXR, through contact a of lever 28G closed in its right-hand or reverse position, over contact b of switch lever 18W closed in its reverse position, over front contact a of relay IRWK, over front contact a of relay 3RWK, over contact 0 of lever 3SW closed in its reverse position, contact c of lever 486 closed in either its normal or its right-hand position, over back contact b of relay 4XPR, and through the winding of relay 4LXR to terminal N.

The exit lamp 4LX is now supplied with energy by a circuit which may be traced from terminal B at front contact b of relay lTPSR, over back contact 0 of relay ZRXR, front contact d of relay IRWK, front contact c of relay SRWK, frontcontact c of relay 4LXR, and through the lamp 4LX to terminal N. The lighting of the exit lamp 4LX on the track model diagram indicates to the operator that a route has been established which has this point as its exit point. If the operator is satisfied that the route which has been set up is the one desired, he then operates the push button ZPB which, as previously pointed out, may either form a portion of the structure of the signal lever itself, or may be a separate push button. When contact b of push button ZPB closes, a circuit is established for energizing relay 4XPR, which circuit may be traced from terminal B at contact b of the push button ZPB, through contact e of signal lever 286 closed in its right-hand position, over back contact b of relay ZRXR, front contact b of relay IRWK, front contact b of reIaySRWK, front contact b of relay 4LXR, and through the winding of relay 4XPR to terminal N.

When relay 4XPR picks up, a circuit is established for energizing the route agreement relay ZRHSR, which circuit may be traced from terminal B at front contact b of relay 4LASR, over front contact d of relay 4XPR, front contact e of relay 4LXR, back contact a of relay 4LHSR, front contact b of relay 3RWCR, front contact b of relay IRWCR, through the Winding of relay ZRHSR, over back contact at of relay ZRXR, and through con tact g of signal lever 256 closed in the reverse position to terminal N.

When contact b of relay ZRHSR picks up, it establishes a by-pass circuit around the contact b of push button ZPB in the circuit for energizing relay 4XPR so that relay 4XPR will be maintained over the circuit previously traced even though the contact b of push button ZPB may be subsequently released.

When contact 0 of relay ZRHSR picks up, it interrupts the supply of energy to the Winding of relay 2RASR, this circuit including the back contacts b of relays ZRAHR and ZRBHR, and the front contact a of relay ZRASR, with the result that relay ZRASR releases its contacts. Contact 0 of relay ZRASRlS included in a circuit for energizing the switch locking relays 1LR and 3LR, so that the opening of this contact results in the release of the switch locking relays, their front contacts b and c interrupting the supply of energy to the windings of the switch controlrelays IWR and 3WR, with the result that the switches cannot. be operated at this time with a route established for a. train to move through the interlocking.

Upon the release of the contacts of the switch locking relays, a circuit is established for energizing the winding of the signal control relay ZRBHR, which circuit may be traced from terminal B at front contact 01 of relay 4LASR, over back contact 0 of relay 4TER, back contact a of relay 3 LR; front contact 0 of relay 3RWCR, back contact 0 of relay ZTER, back contact a of relay lLR, back contact 2 of relay ZRASR, front contact d of relay ZRHSR, front contact 2 of relay ISTR, front contact e of relay ITPSR, front contact c of relay IRWCR, and through the winding of relay ZRBHR to terminal N. When relay ZRBHR picks up, its contact a interrupts the supply of energy to the red lamp R of signal ZRB and establishes an obvious circuit for supplying energy to the yellow lamp Y of the signal, so that the signal displays a caution aspect for the train which is to move through the interlocking plant.

When the train passes signal ZRB and enters the interlocking, the wheels and axles of the train shunt the track section 1T, with the result that track relay lTR releases its contacts. When contact a of relay 1TR releases, it interrupts the supply of energy to the winding of the track repeating stick relay lTPSR, the contacts of which then release, front contact a of this relay interrupting its own stick circuit.

Front contact 2 of relay llTPSR releases to interrupt the supply of energy to the winding of relay ZRBHB, and the contacts of this relay release, contact a of relay ZRBHB interrupting the supply of energy to the yellow lamp Y of signal ZRB and establishing a circuit for supplying energy to the red lamp R of this signal, so that signal 211B is restored to display a stop aspect. Front contact b of track relay ITR further interrupts the control circuit for the switch locking relays. ILR and SLR, so that these relays remain released at this time, preventing the operation of the track switches while a train is moving through the inter-locking.

The release of front contact b of relay ITPSR interrupts the circuit previously traced for supplying energy to the exit lamp 4LX, so that this. lamp is extinguished at this time. At the same time, back contact e of track relay ITR establishes an obvious circuit for supplying energy to the track indication lamp ITKE of the track model diagram, so that the operator of the interlocking machine is made aware of the fact that the train has entered section 1T.

When the train moves over crossover 3, and shunts section 31", the contacts of track relay 3TR will release, front contact a of this relay interrupting the supply of energy to the Winding of the track repeating stick relay STPSR, which accordingly releases its contacts, its front contact a interrupting the stick circuit for this relay, although the pickup circuit for the relay will remain closed through front contacts f of relays 4LASR and 4RASR, and the contact i of signal lever 486 closed in its normal position, so that when the contact a of relay 3TR again picks up, relay 3TPSR will pick up immediately thereafter, its from contact a reestablishing the stick circuit for the relay. The opening of front contact b of relay 3TR further interrupts the circuit for energizing the switch locking relay SLR, to maintain this relay deenergized to prevent operation of the switch movements SSM and 3ASM at this time.

Although front contact 0 of relay 3TR is open at this time in the pickup circuit for the route locking relay TLWSR, this relay remains picked up through the stick circuit including front contact a of relay 1WSR and front contact e of relay 4LASR.

Back contact of relay STR establishes an obvious circuit for supplying energy to the track indication lamp STKE on the track model diagram to inform the operator of the interlocking machine that the train has entered section. 3T. Back contact'e of track relay STR further interrupts the control circuit for the signal control relay ZRBHR, so that this signal cannot be cleared at this time with the train occupying section 3T and with the cross over 3 in its reverse position.

Assuming now that the train has moved over switch 1 and the upper portion of crossover 3, so that section IT is now unoccupied, track relay lTR will again be energized and its contacts will pick up. Although front contact a of relay lTR is now closed in the circuit for energizing relay lTPSR, energy will not be supplied to the winding of relay ITPSR at this time, since the pickup circuit for this relay remains open at front contact 7 of relay ZRASR, as well as contact i of signal level 28G.

If the operator now restores signal lever 256 to its center or normal position, the circuit previously traced for energizing relay 4LXR, which circuit included con- (tact a of signal lever ZSG, will be opened, with the result that relay 4LXR will have the pickup circuit for itself opened at this point. Although relay 4LXR is picked up at this time over the stick circuit including its own front contact a and front contact b of relay 4XPR, relay 4XPR will be deenergized by the operation of contact e of signal lever ZSG to its normal position, so that relay 4XPR releases, interrupting the stick circuit for relay 4LXR which also then releases.

With contact d of relay 4XPR released, and contact e of relay 4LXR released, the circuit previously traced for energizing relay ZRHSR is opened at this point, as well as at contact g of signal lever 28G, 50 that relay ZRHSR releases its contacts. Contact d of relay ZRHSR further interrupts the circuit previously traced for energizing relay ZRBHR, and a circuit is now established for energizing the signal locking relay ZRASR, which circuit may be traced from terminal B at back contact of relay ZRHSR, over back contact b of relay ZRAHR, back contact b of relay ZRBHR, back contact d of relay lTPSR, and through the winding of relay ZRASR to terminal N. When relay 2RASR picks up, its front contact a estab- 'lishes a stick circuit for by-passing the back contact of relay lTPSR, so that relay ZRASR will be maintained picked up after relay lTPSR picks up. Relay lTPSR mow picks up over the circuit including front contact 1 of relay ZRASR and contact i of signal lever 28G, and its stick circuit is established over front contact a of relay ITPSR so that the relay now remains up as long as track relay lTR is energized. When relay ZRASR picks up, its front contact 0 is closed in the circuit for energizing relay lLR, which is now supplied with energy over front contact 0 of relay ZRASR, front contact 0 of relay ZLASR, front contact b of relay ITR, and front contact b of the route locking relay IWSR. When contacts b and r: of relay lLR pick up, they reestablish the circuit for supplying energy to the winding of the switch control relay llWR, so that, if desired, the switch 1W may be operated at this time even though the train is still proceeding through section 3T.

When the train vacates section 3T, the contacts of relay 3TR will pick up, contact a of the relay establishing a previously traced pickup circuit for relay 3TPSR, which then sticks up over front contact a of the relay, front contact b of relay 3TR reclosing in the circuit for energizing relay SLR, so that relay 3LR picks up at this time to thereby reenergize the switch control relay 3WR, and back contact f of relay 3TR interrupting the supply of energy to the track indication lamp 3TKE. The operator may now restore the crossover 3 to its normal position if so desired by operating the switch lever 3SW to its left-hand or normal position, to thereby energize the switch control relay 3WR with energy of normal polarity so that the contacts of the relay are operated to their normal position, whereby energy is supplied to the switch movements 38M and SASM to operate the track switches to their normal position. The switch indication circuits for the track switch 1 and crossover 3 will operate in the normal manner to supply either normal or reverse switch correspondence indications by the pickup of the switch correspondence relays associated with the particular position of the switch, and the switch indication relays such as INWK and SNWK controlled by the switch correspondence relays will be energized at this time, so that the apparatus is restored to its normal condition as shown in the drawings and as previously described.

It will now be assumed that it is desired to clear signal 4L for a train movement over the crossover 3 reversed and the switch 1 reversed, which, it will be seen, is a train movement similar to the one described except in the opposite direction. Accordingly, the switch levers 18W and SSW will be positioned to their reverse position to cause corresponding operation of the switch and crossover, and resultant operation of the switch correspondence and switch indication relays as previously described, following which the signal lever 4SG will be operated to its left-hand position.

Acircuit is accordingly established for energizing relay ZRXR, which circuit may be traced from terminal B at back contact a of relay 4LXR, through contact d of lever 48G closed in the left-hand position, over contact 0 of lever 38W closed in the reverse position, front contact a of relay 3RWK, front contact a of relay IRWK, contact b of switch lever ISW closed in its reverse position, over contact b of lever 25G closed in either the normal or the left-hand position, over back contact a of relay ZXPR, and through the winding of relay ZRXR to terminal N. When relay ZRXR picks up, a circuit is established for supplying energy to the exit lamp ZRBX, which circuit may be traced from terminal B at front contact b of relay STPSR, over back contact c of relay 4LXR, front contact 0 of relay 3RWK, front contact d of relay IRWK, front contact 0 of relay ZRXR, front contact 0 of relay IRWK, and through the lamp 2RBX to terminal N. Accordingly, lamp 2RBX is lighted in the track model diagram to indicate to the operator of the interlocking machine that a route has been set up through the track layout which has the point designated by the exit lamp 2RBX as the exit point for the route. If this route is in accordance with that desired by the operator, he then depresses the push button 4PB associated with the signal lever 4SG. A circuit is thereby established for energizing relay ZXPR, which circuit may be traced from terminal B at contact a of push button 4PB, through contact of signal lever 48G closed in the left-hand position, over back contact b of relay 4LXR, front contact b of relay 3RWK, front contact b of relay lRWK, front contact b of relay ZRXR, and through the winding of relay ZXPR to terminal NJ When relay ZXPR picks up, it establishes a stick circuit for main taining relay ZRXR energized, which circuit may be traced from terminal B at front contact a of relay ZRXR, over front contact a of relay ZXPR, and through the winding of relay ZRXR to terminal N, so that relays ZRXR and ZXPR are both picked up at this time.

Relay 4LHSR is now energized by a circuit which may be traced from terminal B at front contact b of relay ZRASR, over front contact 0 of relay ZXPR, front contact e of relay ZRXR, back contact a of relay ZRHSR, front contact b of relay IRWCR, front contact b of relay 3RWCR, through the winding of relay 4LHSR, over back contact 0! of relay 4LXR, and through contact h of signal lever 4SG in its left-hand position to terminal N. When relay 4LHSR picks up, its front contact b establishes a circuit for by-passing the contact a of push button 4PB so that a circuit for maintaining relay 2XPR is closed even though the contact a of push button 4PB is thereafter I opened by the operator releasing the push button.

When relay 4LHSR picks up, its back contact 0 interrupts the circuit for supplying energy to relay 4LASR, so that relay 4LASR releases its contacts. When contact c of relay 4LASR opens, the circuit for supplying energy to the winding of relay SLR is interrupted and as a consequence the contacts of relay 3LR are released; Additionally, when contact e of relay 4LASR releases, since contact at of relay 3NWCR is released at this time, the circuit for energizing relay IWSR is opened and the contacts of this relay release, front contact b of relay IWSR .interrupting the supply of energy to the winding of relay 1LR, so that relay 1LR releases. Thus, the switch locking relays for switch 1 and crossover 3 are both deenergized, their contacts b and c interrupting the supply of energyto the windings of the switch control relays IWR and 3WR so that the switches cannot be operated at this time.

A circuit is now established for energizing the wind ing of signal control relay 4LHR, which circuit may be traced from terminal B at front contact 2 of relay ZRASR, over back contact a of relay 1LR, back contact of relay ZTER, front contact c of relay 3RWCR, back contact a of relay 4LR, back contact c of relay 4TER, back contact d of relay 4LASR, front contact d of relay 4LHSR, front contact d of relay 1TR, front contact e of relay 3TPSR, and through the winding of relay 4LHR to terminal N. When relay 4LHR picks up, its contact a interrupts the supply of energy to the red lamp R of signal 4L and establishes the supply of energy to the yellow lamp Y of this signal, to thereby provide a suitable aspect for the train to enter the interlocking and move over crossover 3 and switch 1 reversed and depart from the interlocking at the location of signal ZRB.

When the train proceeds past signal 4L, track relay 3TR will be released, with the subsequent release of relay STPSR, so that the circuit for relay 4LHR is interrupted and this relay releases to thereby cause signal 4L to again display a red or stop aspect.

5 Contact b of relay 3TR in the circuit for energizing relay 3LR is open at this time to further interrupt the supply. of energy to the winding of relay 3LR to thereby maintain the crossover 3 locked during the train move ment. Contact c of relay 3TR further interrupts the pickup circuit for the route locking relay IWSR, so that contact b of this relay maintains the circuit for the switch locking relay 1LR interrupted with the result that switch 1. cannot be interrupted with the train moving through the interlocking over this route. Back contact 1 of relay 3TR establishes a circuit for energizing the track indication lamp 3TKE so that the operator is notified that the train is occupying section 3T. As the train moves over the crossover 3 and shunts track section 1T, track relay 1TR will release, its front contact d further interrupting the circuit for energizing relay 4LHR, and its front contact b further interrupting the supply of energy to the switch locking relays 1LR and 3LR.

When the rear of the train vacates section 3T, relay SIR will pick up and its front contact a will againbe closed in the pickup circuit for relay 3TPSR, and if in themeantime, the operator has restored the signal lever 45G to its normal position, so that relays ZRXR, ZXPR, and 4LHSR are released, the circuit is established. for energizing relay 4LASR over back contact 0 of relay STPSR, so that relay 4LASR will pick up its contacts. Contact) of relay 4LASR picks up, and the circuit including front contact a of relay 3TR, the winding of relay 3TPSR, front contact of relay 4LASR, front contact f of ,relay 4RASR, and the contact i of signal lever 48G closed in its normal position will now be established to energize the winding of relay 3TPSR, which will pick up, its front contact a reestablishing the stick circuit for this relay. The circuit previously traced for energizing relay 4LHR is now interruptedat contact d of relay 4LASR, contact at of relay 4LHSR, and contact at of relay lTR, so that relay 4LHR remains deenergized.

As the train successively occupies and vacates sections 3T and IT, the releaseand pickup of relays 3TR and 1TR will cause the according operation of the track indication lan'ips 3TKE and lTKE to indicate to the operator of the interlocking machine the location of the train as it moves through these track sections.

"When the train finally vacates section 1T, contact 5 of relay lTR will again be picked up, and the switch locking relay IWSR will be picked up by the circuit including front contact e of relay 4LASR, front contact 0 of relay 3TR, and the winding of relay IWSR, so that this relay picks up and reestablishes its stick circuit in cluding its own front contact a. With contact b of relay IWSR now picked up, the circuit previously traced for energizing relay 1LR is reestablished, as well as the circuit for energizing relay SLR. Accordingly, the switch 1 and crossover 3 may be now operated to their normal position if so desired.

When the switch levers 1SW and 38W are restored to their normal position with according operation of the switch 1 and crossover 3 to their normal position followed by the operation of the switch correspondence and switch indication relays to correspond with these positions, the apparatus is restored to its normal condition as shown in the drawings and originally described.

Considering now the operation of the apparatus for a through movement on one of the main tracks which does not involve the reversed position of the crossover 3 or switch 1, it will be considered that the operator clears signal 4RG for a train to move through the track layout from signal 4R6 to the exit point corresponding to the exit lamp 4LX on the track model diagram. Accordingly, with the switch levers 1SW and. 3SW remaining in their normal position, the signal lever 486 is operated to its right-hand position.

A circuit is now established for energizing relay 4LXR, which circuit may be traced from terminal B at back contact a of relay 4RXR, through contact a of signal lever 48G closed in the right-hand position, over front contact b of relay SNWK, over contact b of the switch lever SSW closed in its normal position, over contact 0 of lever 486 closed in either its normal or its right-hand position, over back contact b of relay 4XPR, and through the winding of relay 4LXR to terminal N.

When relay 4LXR picks up, a circuit is established for energizing the exit lamp 4LX, which circuit may be traced from terminal B at front contact b of relay STPSR, over back contact 0 of relay 4RXR, front contact e of relay 3NWK, front contact 0 of relay 4LXR, and through the lamp 4LX to terminal N.

The display of the exit lamp 4LX indicates to the operator of the interlocking machine that a route has been set up having this point as its exit from the track 'layout, and if the operator desires the signal to be cleared for the established route as indicated, he then depresses the push button 4PB associated with the signal lever 4SG. When contact b of push button 4PB is closed, a circuit is established for energizing relay 4XPR, which circuit may be traced from terminal B at contact b of push button 4-PB, through contact e of lever 486 closed in the right-hand position, over back contact b of relay 4RXR, front contact d of relay 3NWK, front contact b of relay 4LXR, and through the winding of relay 4XPR to terminal N. 7

When relay SXPR picks up, a circuit is established for maintaining relay 4LXR energized, which circuit may be traced from terminal B at front contact a of relay 4LXR, over front contact b of relay XPR, and through the winding of relay 4LXR to terminal N.

Relay 4RHSR is now energized by a circuit which may be traced from terminal B at front contact b of relay 4LASR, over front contact d of relay -XPR, front contact 6 of relay 4LXR, back contact a of relay 4LHSR, front contact 0 of relay BNWCR, through the winding of relay 4RHSR, over back contact d of relay lRXR, and through the contact g of lever 48G closed in the righthand position to terminal N. When relay 4RHSR picks up, its back contact 0 interrupts the supply of energy to the Winding of relay lRASR, With the result that relay 4RASR releases to thereby deenergize the switch locking relay SLR, so that this relay releases to thereby prevent the crossover 3 from being operated at this time. It

11 will be noted that with the route set up for a through movement on the lowermain track, the switch 1 is not locked at this time, so that it may be operated between its normal and reverse positions for any train movements which involve the upper main track and the siding connected thereto by switch 1.

A circuit is now established for energizing the signal control relay 4RHR, which circuit may be traced from terminal B at front contact d of relay 4LASR, over back contact c of relay 4TER, back contact a of relay 3LR, front contact g of relay SNWCR, back contact e of relay 4RASR, front contact at of relay lRHSR, front contact f of relay 3TPSR, and through the winding of relay 4RHR to terminal N.

When relay 4RHR picks up, its contact a interrupts the supply of energy to the red lamp R of signal 4R and establishes a supply of energy to the yellow lamp Y of this signal to thereby cause this signal to display an aspect to permit the train to move through the track layout.

When the train passes signal 4R and enters track section 3T, track relay 3TB. will release, its contacts interrupting the supply of energy to the winding of relay 3TPSR, so that this relay releases, and also causing a supply of energy to the indication lamp STKE to indicate to the operator that the train is occupying this section. As previously pointed out, the operator may now restore the signal lever 48G to its normal position, to thereby cause the release' of relays dLXR and 4XPR, the exit lamp 4LX being extinguished when the relay STPSR is released.

When the train moves out of section 3T, relay STPSR will again be energized, and the switch locking circuits will be energized so that the switch 1 and crossover 3 may again be operated to either their normal or reverse position as desired. With signal lever 45G restored to its normal position, and the switch levers 18W and 38W remaining their normal positions, the apparatus will be restored to its normal condition as shown in the drawings.

From the foregoing, it will be seen that my invention provides a novel arrangement for governing the operation of an allrelay railway interlocking control system, in which suitable exit lamps are provided on the track model diagram for indicating to the operator of the interlocking machine the point of exit of a route which has been set up. If this route is in agreement with the desires of the operator, a further operation controlled by the operator may be initiated to maintain this route, and to provide for the clearing of the associated signal to permit a train to move over the route and make its exit from the track layout at the designated point. These features are provided by a system of exit relays, one for each point of exit in the track layout, which exit relays are controlled by contacts of the associated switch and signal levers, together with the contacts of switch indication relays which indicate the position of the track switches involved. When a selected one of the exit relays has been energized in accordance with a route set up by the operator, the subsequent operation of a push button or other manually operated means causes the pickup of an exit relay repeater relay through a suitable circuit network which checks the position of the track switches involved and the signal levers, as well as the contacts of the exit relays, these exit relay repeater relays providing a suitable stick circuit for the exit relays, so that the exit relays and exit relay repeater relays are thereafter maintained energized, even though the push button or other manually controllable device is thereafter operated to its noneffective position. The exit relays and exit repeater relays cooperate with circuit networks including contacts of switch correspondence relays which check the correspondence between the switch control. circuits and the actual position of the track switches, to thereby energize route agreement relays, which, when energized, close appropriate contacts in a signal control network which in turn checks the position of the track switches, the locked condition of the switches, and the track occupancy conditions of the various routes, to accordingly clear the appropriate wayside signals to permit train movements.

Although I have herein shown and described only one form of railway interlocking control system embodying my invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A railway interlocking control system for a track layout including a route between opposing signals comprising a stretch of track and one or more switches in said stretch in predetermined positions, operating means for positioning each switch, a switch lever for each switch settable in accordance with the desired position of the switch and connected to control said switch operating means, a signal lever settablc to one position to designate one of said signals as an entrance signal and to another position to designate the other of said signals as an en trance signal, switch indication means controlled by each switch to indicate the position thereof, an exit relay for each signal; an energizing circuit for each exit relay com prising contacts closed by each switch lever when set in accordance with said predetermined position of the switch for said route, contacts closed by the switch indication means when each switch is in said predetermined position for said route, and a contact closed by the signal lever when set to designate the opposing signal; a push button, an exit relay repeater relay, circuit means'for energizing said exit relay repeater relay when said path button is actuated and said exit relays are in opposite positions, circuit means including front contacts of said exit relay repeater relay for maintaining said exit relays energized, an exit lamp for each exit relay, an energizing circuit for each exit lamp including a front contact of the corresponding exit relay, and circuit means for controlling each signal to a clear aspect including a front contact of the exit relay for the opposing signal and 'a front contact of said exit relay repeater relay.

2. A railway interlocking control system for a track layout including a route between opposing signals comprising one or more track sections in a stretch of track and one or more switches in said stretch in predetermined positions; operating means for positioning each switch, a switch lever for each switch settable in accordance with the desired position of the switch and connected to control said switch operating means, a signal lever settable to one position to designate one of said signals as an entrance signal and to another position to designate the other of said signals as an entrance signal, switch indication means controlled by each switch to indicate the position thereof, an exit relay for each signal, an energizing circuit for each exit relay comprising contacts closed by each switch lever when set in accordance with the predetermined position of the switch for said route, contacts closed by the switch indication means when each switchisin said predetermined position, and a contact closed by the signal lever when set to designate the opposing signal; a push button, an exit relay repeater relay, circuit means for energizing said exit relay repeater relay when said push button is actuated and said exit relays are in opposite positions, circuit means including front contacts of said exit relay repeater relay for maintaining said exit relays energized, an exit lamp for each exit relay, an energizing circuit'for each exit lamp including a front contact of the corresponding exit relay, circuit means for controlling each signal to a clear aspect including a front contact of the exit relay for the opposing signal and a front contact of said exit relay repeater relay, track relay means for detecting occupancy of each said track section, and means controlled by said track relay means for deenergizing each exit lamp when a train enters said track stretch.

3. A railway interlocking control system for a track layout including a route between opposing signals comprising a stretch of track and one or more switches in said stretch in predetermined positions, operating means for positioning each switch, a switch lever for each switch settable in accordance with the desired position of the switch and connected to control said switch operating means; a signal lever settable to one position to designate one of said signals as an entrance signal and to another position to designate the other of said signals as an en trance signal, switch indication means controlled by each switch to indicate the position thereof, an exit relay for each signal; an energizing circuit for each exit relay comprising contacts closed by each switch lever when set in accordance with said predetermined position of the switch for said route, contacts closed by the switch indication means when each switch is in said predetermined position, and a contact closed by the signal lever when set to designate the opposing signal; a push button, an exit relay repeater relay, circuit means for energizing said exit relay repeater relay when said push button is actuated and said exit relays are in opposite positions, circuit means including front contacts of said exit relay repeater relay for maintaining said exit relays energized, an exit lamp for each exit relay, an energizing circuit for each exit lamp including a front contact of the corresponding exit relay, 9. switch correspondence relay for each switch, circuit means for energizing each switch correspondence relay when the corresponding switch is in said predetermined position and its switch lever is set in accordance with said predetermined position, a route agreement relay for each signal; circuit means for energizing each route agreement relay when said switch correspondence relays are energized, said signal lever is set to designate the corresponding signal, the exit relay for the corresponding signal is deenergized, the route agreement relay for the opposing signal is deenergized, the exit relay for the opposing signal is energized, and said exit relay repeater relay is energized; and circuit means for controlling each signal to a clear aspect when the corresponding route agreement relay is energized.

4. A railway interlocking control system for a track layout including a route between opposing signals comprising one or more track sections in a stretch of track and one or more switches in said stretch in predetermined positions; operating means for positioning each switch, a switch lever for each switch settable in accordance with the desired position of the switch and connected to control said switch operating means, a signal lever settable to one position to designate one of said signals as an entrance signal and to another position to designate the other of said signals as an entrance signal, switch indication means controlled by each switch to indicate the position thereof, an exit relay for each signal; an energizing circuit for each exit relay comprising contacts closed by each switch lever when set in accordance with said predetermined position of the switch for said route, contacts closed by the switch indication means when each switch is in said predetermined position for said route, and a contact closed by the signal lever when set to designate the opposing signal; a push button, an exit relay repeater relay, circuit means for energizing said exit relay repeater relay when said push button is actuated and said exit relays are in opposite positions, circuit means including front contacts of said exit relay repeater relay for maintaining said exit relays energized, an exit lamp for each exit relay, an energizing circuit for each exit lamp including a front contact of the corresponding exit relay, a switch correspondence relay for each switch, circuit means for energizing each switch correspondence relay when the corresponding switch is in said predetermined position and its switch lever is set in accordance with said predetermined position, a route agreement relay for each signal; circuit means for energizing each route agreement relay when said switch correspondence relays are energized, said signal lever is set to designate the corresponding signal, the exit relay for the corresponding signal is deenergized, the route agreement relay for the opposing signal is deenergized, the exit relay for the opposing signal is energized, and said exit relay repeater relay is energized; circuit means for controlling each signal to a clear aspect when the corresponding route agreement relay is energized, track relay means for detecting the occupancy of each said track section, and means controlled by said track relay means for deenergizing each exit lamp when a train enters said track stretch.

References Cited in the file of this patent UNITED STATES PATENTS 2,133,627 McCann Oct. 18, 1938 2,245,082 Preston et a1 June 10, 1941 2,265,240 Langdon Dec. 9, 1941 2,300,272 Young Oct. 27, 1942 2,302,007 Coley Nov. 17, 1942 2,439,676 Seitz Apr. 13, 1948 2,567,834 Allen Sept. 11, 1951 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,891,142 June 16, 1.959

Clifford D, Ihrig It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that "the said Letters Patent should read as corrected below.

Column 12, line 36, for "path" read m push o Signed and sealed this 13th day of October 1959,

(SEAL)- Attest:

KARL H. AXLINE ROBERT c. WATSON Attesting Oflicer Commissioner of Patents 

